1. Field of the Invention
The present invention relates to a cooling device having a cooling part movably provided with respect to an image forming apparatus main body, and an image forming apparatus having the cooling device.
2. Description of the Related Art
Some image forming apparatuses such as copiers, printers, facsimiles, or multi-function machines have a cooling device for cooling units provided around a unit such as a fixing unit that generates heat. For example, Patent Document 1 describes an image forming apparatus having a liquid-cooled cooling device that cools a process unit detachable from an image forming apparatus main body.
Further, for the purpose of achieving a high printing speed, an amount of heat applied to a sheet at image fixation has increased recently, which in turn easily causes the phenomenon so-called “blocking” in which softened toner is attached to another sheet and problems such as the curling of sheets. In order to prevent such problems, a sheet discharged from a fixing unit is cooled by a cooling unit. For example, Patent Document 2 describes an image forming apparatus having a heat pipe as a unit that cools sheets.
Generally, a fixing unit, a process unit, and the like are configured to be detachable from an image forming apparatus main body so that a maintenance operation and processing for addressing sheet jams can be performed. Further, since the fixing unit is at high temperature immediately after the stoppage of its operations, it is desired to perform the maintenance operation and the processing for addressing sheet jams after the fixing unit is cooled by the cooling unit. Similarly, since there is a likelihood that the process unit and the like would be heated by the fixing unit, it is better to perform the maintenance operation and the processing for addressing sheet jams after the process unit and the like are cooled.
However, in the case of the image forming apparatus described in Patent Document 1, when the process unit is detached from the image forming apparatus main body, a cooling pipe provided in the process unit is separated from a circulation pump provided in the image forming apparatus main body. In this situation, the process unit is not cooled. Therefore, at the time of performing the maintenance operation and the like, there is a high likelihood that the process unit would still be at high temperature, and thus an operator would be at risk when touching the process unit. Further, if cooling liquid remaining at a connection part (separation part) between the cooling pipe and the circulation pump were to fall into the image forming apparatus when the cooling pipe is separated from the circulation pump, subsequent image formation would be adversely affected. Moreover, if foreign matter such as toner and sheet powder scattered in the image forming apparatus were attached to the cooling liquid remaining at the connection part (separation part), the foreign matter would intrude into the cooling device to cause the degradation of the cooling liquid, a failure in the circulation pump, and the like.
On the other hand, if the circulation pump were integrated with the process unit, it could also be possible to circulate the cooling liquid even when the process unit is detached from the image forming apparatus main body. In this case, however, the process unit would need to be upsized, which in turn degrades the performance of the maintenance operation and the ability of addressing sheet jams. In addition, the upsizing of the process unit makes necessary improving the strength of a housing that supports the process unit, which in turn runs counter to the downsizing and the weight reduction of the process unit.
Further, the above problems could occur not only in the process unit but also in the fixing unit and other units required to be cooled.
Patent Document 1: JP-A-2006-3628
Patent Document 2: JP-A-10-207155